1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> 4 5 This program can be distributed under the terms of the GNU GPL. 6 See the file COPYING. 7 */ 8 9 #include "fuse_i.h" 10 11 #include <linux/init.h> 12 #include <linux/module.h> 13 #include <linux/poll.h> 14 #include <linux/sched/signal.h> 15 #include <linux/uio.h> 16 #include <linux/miscdevice.h> 17 #include <linux/pagemap.h> 18 #include <linux/file.h> 19 #include <linux/slab.h> 20 #include <linux/pipe_fs_i.h> 21 #include <linux/swap.h> 22 #include <linux/splice.h> 23 #include <linux/sched.h> 24 25 MODULE_ALIAS_MISCDEV(FUSE_MINOR); 26 MODULE_ALIAS("devname:fuse"); 27 28 /* Ordinary requests have even IDs, while interrupts IDs are odd */ 29 #define FUSE_INT_REQ_BIT (1ULL << 0) 30 #define FUSE_REQ_ID_STEP (1ULL << 1) 31 32 static struct kmem_cache *fuse_req_cachep; 33 34 static struct fuse_dev *fuse_get_dev(struct file *file) 35 { 36 /* 37 * Lockless access is OK, because file->private data is set 38 * once during mount and is valid until the file is released. 39 */ 40 return READ_ONCE(file->private_data); 41 } 42 43 static void fuse_request_init(struct fuse_mount *fm, struct fuse_req *req) 44 { 45 INIT_LIST_HEAD(&req->list); 46 INIT_LIST_HEAD(&req->intr_entry); 47 init_waitqueue_head(&req->waitq); 48 refcount_set(&req->count, 1); 49 __set_bit(FR_PENDING, &req->flags); 50 req->fm = fm; 51 } 52 53 static struct fuse_req *fuse_request_alloc(struct fuse_mount *fm, gfp_t flags) 54 { 55 struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags); 56 if (req) 57 fuse_request_init(fm, req); 58 59 return req; 60 } 61 62 static void fuse_request_free(struct fuse_req *req) 63 { 64 kmem_cache_free(fuse_req_cachep, req); 65 } 66 67 static void __fuse_get_request(struct fuse_req *req) 68 { 69 refcount_inc(&req->count); 70 } 71 72 /* Must be called with > 1 refcount */ 73 static void __fuse_put_request(struct fuse_req *req) 74 { 75 refcount_dec(&req->count); 76 } 77 78 void fuse_set_initialized(struct fuse_conn *fc) 79 { 80 /* Make sure stores before this are seen on another CPU */ 81 smp_wmb(); 82 fc->initialized = 1; 83 } 84 85 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background) 86 { 87 return !fc->initialized || (for_background && fc->blocked); 88 } 89 90 static void fuse_drop_waiting(struct fuse_conn *fc) 91 { 92 /* 93 * lockess check of fc->connected is okay, because atomic_dec_and_test() 94 * provides a memory barrier matched with the one in fuse_wait_aborted() 95 * to ensure no wake-up is missed. 96 */ 97 if (atomic_dec_and_test(&fc->num_waiting) && 98 !READ_ONCE(fc->connected)) { 99 /* wake up aborters */ 100 wake_up_all(&fc->blocked_waitq); 101 } 102 } 103 104 static void fuse_put_request(struct fuse_req *req); 105 106 static struct fuse_req *fuse_get_req(struct fuse_mount *fm, bool for_background) 107 { 108 struct fuse_conn *fc = fm->fc; 109 struct fuse_req *req; 110 int err; 111 atomic_inc(&fc->num_waiting); 112 113 if (fuse_block_alloc(fc, for_background)) { 114 err = -EINTR; 115 if (wait_event_killable_exclusive(fc->blocked_waitq, 116 !fuse_block_alloc(fc, for_background))) 117 goto out; 118 } 119 /* Matches smp_wmb() in fuse_set_initialized() */ 120 smp_rmb(); 121 122 err = -ENOTCONN; 123 if (!fc->connected) 124 goto out; 125 126 err = -ECONNREFUSED; 127 if (fc->conn_error) 128 goto out; 129 130 req = fuse_request_alloc(fm, GFP_KERNEL); 131 err = -ENOMEM; 132 if (!req) { 133 if (for_background) 134 wake_up(&fc->blocked_waitq); 135 goto out; 136 } 137 138 req->in.h.uid = from_kuid(fc->user_ns, current_fsuid()); 139 req->in.h.gid = from_kgid(fc->user_ns, current_fsgid()); 140 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns); 141 142 __set_bit(FR_WAITING, &req->flags); 143 if (for_background) 144 __set_bit(FR_BACKGROUND, &req->flags); 145 146 if (unlikely(req->in.h.uid == ((uid_t)-1) || 147 req->in.h.gid == ((gid_t)-1))) { 148 fuse_put_request(req); 149 return ERR_PTR(-EOVERFLOW); 150 } 151 return req; 152 153 out: 154 fuse_drop_waiting(fc); 155 return ERR_PTR(err); 156 } 157 158 static void fuse_put_request(struct fuse_req *req) 159 { 160 struct fuse_conn *fc = req->fm->fc; 161 162 if (refcount_dec_and_test(&req->count)) { 163 if (test_bit(FR_BACKGROUND, &req->flags)) { 164 /* 165 * We get here in the unlikely case that a background 166 * request was allocated but not sent 167 */ 168 spin_lock(&fc->bg_lock); 169 if (!fc->blocked) 170 wake_up(&fc->blocked_waitq); 171 spin_unlock(&fc->bg_lock); 172 } 173 174 if (test_bit(FR_WAITING, &req->flags)) { 175 __clear_bit(FR_WAITING, &req->flags); 176 fuse_drop_waiting(fc); 177 } 178 179 fuse_request_free(req); 180 } 181 } 182 183 unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args) 184 { 185 unsigned nbytes = 0; 186 unsigned i; 187 188 for (i = 0; i < numargs; i++) 189 nbytes += args[i].size; 190 191 return nbytes; 192 } 193 EXPORT_SYMBOL_GPL(fuse_len_args); 194 195 u64 fuse_get_unique(struct fuse_iqueue *fiq) 196 { 197 fiq->reqctr += FUSE_REQ_ID_STEP; 198 return fiq->reqctr; 199 } 200 EXPORT_SYMBOL_GPL(fuse_get_unique); 201 202 static unsigned int fuse_req_hash(u64 unique) 203 { 204 return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS); 205 } 206 207 /** 208 * A new request is available, wake fiq->waitq 209 */ 210 static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq) 211 __releases(fiq->lock) 212 { 213 wake_up(&fiq->waitq); 214 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 215 spin_unlock(&fiq->lock); 216 } 217 218 const struct fuse_iqueue_ops fuse_dev_fiq_ops = { 219 .wake_forget_and_unlock = fuse_dev_wake_and_unlock, 220 .wake_interrupt_and_unlock = fuse_dev_wake_and_unlock, 221 .wake_pending_and_unlock = fuse_dev_wake_and_unlock, 222 }; 223 EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops); 224 225 static void queue_request_and_unlock(struct fuse_iqueue *fiq, 226 struct fuse_req *req) 227 __releases(fiq->lock) 228 { 229 req->in.h.len = sizeof(struct fuse_in_header) + 230 fuse_len_args(req->args->in_numargs, 231 (struct fuse_arg *) req->args->in_args); 232 list_add_tail(&req->list, &fiq->pending); 233 fiq->ops->wake_pending_and_unlock(fiq); 234 } 235 236 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, 237 u64 nodeid, u64 nlookup) 238 { 239 struct fuse_iqueue *fiq = &fc->iq; 240 241 forget->forget_one.nodeid = nodeid; 242 forget->forget_one.nlookup = nlookup; 243 244 spin_lock(&fiq->lock); 245 if (fiq->connected) { 246 fiq->forget_list_tail->next = forget; 247 fiq->forget_list_tail = forget; 248 fiq->ops->wake_forget_and_unlock(fiq); 249 } else { 250 kfree(forget); 251 spin_unlock(&fiq->lock); 252 } 253 } 254 255 static void flush_bg_queue(struct fuse_conn *fc) 256 { 257 struct fuse_iqueue *fiq = &fc->iq; 258 259 while (fc->active_background < fc->max_background && 260 !list_empty(&fc->bg_queue)) { 261 struct fuse_req *req; 262 263 req = list_first_entry(&fc->bg_queue, struct fuse_req, list); 264 list_del(&req->list); 265 fc->active_background++; 266 spin_lock(&fiq->lock); 267 req->in.h.unique = fuse_get_unique(fiq); 268 queue_request_and_unlock(fiq, req); 269 } 270 } 271 272 /* 273 * This function is called when a request is finished. Either a reply 274 * has arrived or it was aborted (and not yet sent) or some error 275 * occurred during communication with userspace, or the device file 276 * was closed. The requester thread is woken up (if still waiting), 277 * the 'end' callback is called if given, else the reference to the 278 * request is released 279 */ 280 void fuse_request_end(struct fuse_req *req) 281 { 282 struct fuse_mount *fm = req->fm; 283 struct fuse_conn *fc = fm->fc; 284 struct fuse_iqueue *fiq = &fc->iq; 285 286 if (test_and_set_bit(FR_FINISHED, &req->flags)) 287 goto put_request; 288 289 /* 290 * test_and_set_bit() implies smp_mb() between bit 291 * changing and below FR_INTERRUPTED check. Pairs with 292 * smp_mb() from queue_interrupt(). 293 */ 294 if (test_bit(FR_INTERRUPTED, &req->flags)) { 295 spin_lock(&fiq->lock); 296 list_del_init(&req->intr_entry); 297 spin_unlock(&fiq->lock); 298 } 299 WARN_ON(test_bit(FR_PENDING, &req->flags)); 300 WARN_ON(test_bit(FR_SENT, &req->flags)); 301 if (test_bit(FR_BACKGROUND, &req->flags)) { 302 spin_lock(&fc->bg_lock); 303 clear_bit(FR_BACKGROUND, &req->flags); 304 if (fc->num_background == fc->max_background) { 305 fc->blocked = 0; 306 wake_up(&fc->blocked_waitq); 307 } else if (!fc->blocked) { 308 /* 309 * Wake up next waiter, if any. It's okay to use 310 * waitqueue_active(), as we've already synced up 311 * fc->blocked with waiters with the wake_up() call 312 * above. 313 */ 314 if (waitqueue_active(&fc->blocked_waitq)) 315 wake_up(&fc->blocked_waitq); 316 } 317 318 fc->num_background--; 319 fc->active_background--; 320 flush_bg_queue(fc); 321 spin_unlock(&fc->bg_lock); 322 } else { 323 /* Wake up waiter sleeping in request_wait_answer() */ 324 wake_up(&req->waitq); 325 } 326 327 if (test_bit(FR_ASYNC, &req->flags)) 328 req->args->end(fm, req->args, req->out.h.error); 329 put_request: 330 fuse_put_request(req); 331 } 332 EXPORT_SYMBOL_GPL(fuse_request_end); 333 334 static int queue_interrupt(struct fuse_req *req) 335 { 336 struct fuse_iqueue *fiq = &req->fm->fc->iq; 337 338 spin_lock(&fiq->lock); 339 /* Check for we've sent request to interrupt this req */ 340 if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) { 341 spin_unlock(&fiq->lock); 342 return -EINVAL; 343 } 344 345 if (list_empty(&req->intr_entry)) { 346 list_add_tail(&req->intr_entry, &fiq->interrupts); 347 /* 348 * Pairs with smp_mb() implied by test_and_set_bit() 349 * from fuse_request_end(). 350 */ 351 smp_mb(); 352 if (test_bit(FR_FINISHED, &req->flags)) { 353 list_del_init(&req->intr_entry); 354 spin_unlock(&fiq->lock); 355 return 0; 356 } 357 fiq->ops->wake_interrupt_and_unlock(fiq); 358 } else { 359 spin_unlock(&fiq->lock); 360 } 361 return 0; 362 } 363 364 static void request_wait_answer(struct fuse_req *req) 365 { 366 struct fuse_conn *fc = req->fm->fc; 367 struct fuse_iqueue *fiq = &fc->iq; 368 int err; 369 370 if (!fc->no_interrupt) { 371 /* Any signal may interrupt this */ 372 err = wait_event_interruptible(req->waitq, 373 test_bit(FR_FINISHED, &req->flags)); 374 if (!err) 375 return; 376 377 set_bit(FR_INTERRUPTED, &req->flags); 378 /* matches barrier in fuse_dev_do_read() */ 379 smp_mb__after_atomic(); 380 if (test_bit(FR_SENT, &req->flags)) 381 queue_interrupt(req); 382 } 383 384 if (!test_bit(FR_FORCE, &req->flags)) { 385 /* Only fatal signals may interrupt this */ 386 err = wait_event_killable(req->waitq, 387 test_bit(FR_FINISHED, &req->flags)); 388 if (!err) 389 return; 390 391 spin_lock(&fiq->lock); 392 /* Request is not yet in userspace, bail out */ 393 if (test_bit(FR_PENDING, &req->flags)) { 394 list_del(&req->list); 395 spin_unlock(&fiq->lock); 396 __fuse_put_request(req); 397 req->out.h.error = -EINTR; 398 return; 399 } 400 spin_unlock(&fiq->lock); 401 } 402 403 /* 404 * Either request is already in userspace, or it was forced. 405 * Wait it out. 406 */ 407 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags)); 408 } 409 410 static void __fuse_request_send(struct fuse_req *req) 411 { 412 struct fuse_iqueue *fiq = &req->fm->fc->iq; 413 414 BUG_ON(test_bit(FR_BACKGROUND, &req->flags)); 415 spin_lock(&fiq->lock); 416 if (!fiq->connected) { 417 spin_unlock(&fiq->lock); 418 req->out.h.error = -ENOTCONN; 419 } else { 420 req->in.h.unique = fuse_get_unique(fiq); 421 /* acquire extra reference, since request is still needed 422 after fuse_request_end() */ 423 __fuse_get_request(req); 424 queue_request_and_unlock(fiq, req); 425 426 request_wait_answer(req); 427 /* Pairs with smp_wmb() in fuse_request_end() */ 428 smp_rmb(); 429 } 430 } 431 432 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args) 433 { 434 if (fc->minor < 4 && args->opcode == FUSE_STATFS) 435 args->out_args[0].size = FUSE_COMPAT_STATFS_SIZE; 436 437 if (fc->minor < 9) { 438 switch (args->opcode) { 439 case FUSE_LOOKUP: 440 case FUSE_CREATE: 441 case FUSE_MKNOD: 442 case FUSE_MKDIR: 443 case FUSE_SYMLINK: 444 case FUSE_LINK: 445 args->out_args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE; 446 break; 447 case FUSE_GETATTR: 448 case FUSE_SETATTR: 449 args->out_args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE; 450 break; 451 } 452 } 453 if (fc->minor < 12) { 454 switch (args->opcode) { 455 case FUSE_CREATE: 456 args->in_args[0].size = sizeof(struct fuse_open_in); 457 break; 458 case FUSE_MKNOD: 459 args->in_args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE; 460 break; 461 } 462 } 463 } 464 465 static void fuse_force_creds(struct fuse_req *req) 466 { 467 struct fuse_conn *fc = req->fm->fc; 468 469 req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid()); 470 req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid()); 471 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns); 472 } 473 474 static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args) 475 { 476 req->in.h.opcode = args->opcode; 477 req->in.h.nodeid = args->nodeid; 478 req->args = args; 479 if (args->end) 480 __set_bit(FR_ASYNC, &req->flags); 481 } 482 483 ssize_t fuse_simple_request(struct fuse_mount *fm, struct fuse_args *args) 484 { 485 struct fuse_conn *fc = fm->fc; 486 struct fuse_req *req; 487 ssize_t ret; 488 489 if (args->force) { 490 atomic_inc(&fc->num_waiting); 491 req = fuse_request_alloc(fm, GFP_KERNEL | __GFP_NOFAIL); 492 493 if (!args->nocreds) 494 fuse_force_creds(req); 495 496 __set_bit(FR_WAITING, &req->flags); 497 __set_bit(FR_FORCE, &req->flags); 498 } else { 499 WARN_ON(args->nocreds); 500 req = fuse_get_req(fm, false); 501 if (IS_ERR(req)) 502 return PTR_ERR(req); 503 } 504 505 /* Needs to be done after fuse_get_req() so that fc->minor is valid */ 506 fuse_adjust_compat(fc, args); 507 fuse_args_to_req(req, args); 508 509 if (!args->noreply) 510 __set_bit(FR_ISREPLY, &req->flags); 511 __fuse_request_send(req); 512 ret = req->out.h.error; 513 if (!ret && args->out_argvar) { 514 BUG_ON(args->out_numargs == 0); 515 ret = args->out_args[args->out_numargs - 1].size; 516 } 517 fuse_put_request(req); 518 519 return ret; 520 } 521 522 static bool fuse_request_queue_background(struct fuse_req *req) 523 { 524 struct fuse_mount *fm = req->fm; 525 struct fuse_conn *fc = fm->fc; 526 bool queued = false; 527 528 WARN_ON(!test_bit(FR_BACKGROUND, &req->flags)); 529 if (!test_bit(FR_WAITING, &req->flags)) { 530 __set_bit(FR_WAITING, &req->flags); 531 atomic_inc(&fc->num_waiting); 532 } 533 __set_bit(FR_ISREPLY, &req->flags); 534 spin_lock(&fc->bg_lock); 535 if (likely(fc->connected)) { 536 fc->num_background++; 537 if (fc->num_background == fc->max_background) 538 fc->blocked = 1; 539 list_add_tail(&req->list, &fc->bg_queue); 540 flush_bg_queue(fc); 541 queued = true; 542 } 543 spin_unlock(&fc->bg_lock); 544 545 return queued; 546 } 547 548 int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args, 549 gfp_t gfp_flags) 550 { 551 struct fuse_req *req; 552 553 if (args->force) { 554 WARN_ON(!args->nocreds); 555 req = fuse_request_alloc(fm, gfp_flags); 556 if (!req) 557 return -ENOMEM; 558 __set_bit(FR_BACKGROUND, &req->flags); 559 } else { 560 WARN_ON(args->nocreds); 561 req = fuse_get_req(fm, true); 562 if (IS_ERR(req)) 563 return PTR_ERR(req); 564 } 565 566 fuse_args_to_req(req, args); 567 568 if (!fuse_request_queue_background(req)) { 569 fuse_put_request(req); 570 return -ENOTCONN; 571 } 572 573 return 0; 574 } 575 EXPORT_SYMBOL_GPL(fuse_simple_background); 576 577 static int fuse_simple_notify_reply(struct fuse_mount *fm, 578 struct fuse_args *args, u64 unique) 579 { 580 struct fuse_req *req; 581 struct fuse_iqueue *fiq = &fm->fc->iq; 582 int err = 0; 583 584 req = fuse_get_req(fm, false); 585 if (IS_ERR(req)) 586 return PTR_ERR(req); 587 588 __clear_bit(FR_ISREPLY, &req->flags); 589 req->in.h.unique = unique; 590 591 fuse_args_to_req(req, args); 592 593 spin_lock(&fiq->lock); 594 if (fiq->connected) { 595 queue_request_and_unlock(fiq, req); 596 } else { 597 err = -ENODEV; 598 spin_unlock(&fiq->lock); 599 fuse_put_request(req); 600 } 601 602 return err; 603 } 604 605 /* 606 * Lock the request. Up to the next unlock_request() there mustn't be 607 * anything that could cause a page-fault. If the request was already 608 * aborted bail out. 609 */ 610 static int lock_request(struct fuse_req *req) 611 { 612 int err = 0; 613 if (req) { 614 spin_lock(&req->waitq.lock); 615 if (test_bit(FR_ABORTED, &req->flags)) 616 err = -ENOENT; 617 else 618 set_bit(FR_LOCKED, &req->flags); 619 spin_unlock(&req->waitq.lock); 620 } 621 return err; 622 } 623 624 /* 625 * Unlock request. If it was aborted while locked, caller is responsible 626 * for unlocking and ending the request. 627 */ 628 static int unlock_request(struct fuse_req *req) 629 { 630 int err = 0; 631 if (req) { 632 spin_lock(&req->waitq.lock); 633 if (test_bit(FR_ABORTED, &req->flags)) 634 err = -ENOENT; 635 else 636 clear_bit(FR_LOCKED, &req->flags); 637 spin_unlock(&req->waitq.lock); 638 } 639 return err; 640 } 641 642 struct fuse_copy_state { 643 int write; 644 struct fuse_req *req; 645 struct iov_iter *iter; 646 struct pipe_buffer *pipebufs; 647 struct pipe_buffer *currbuf; 648 struct pipe_inode_info *pipe; 649 unsigned long nr_segs; 650 struct page *pg; 651 unsigned len; 652 unsigned offset; 653 unsigned move_pages:1; 654 }; 655 656 static void fuse_copy_init(struct fuse_copy_state *cs, int write, 657 struct iov_iter *iter) 658 { 659 memset(cs, 0, sizeof(*cs)); 660 cs->write = write; 661 cs->iter = iter; 662 } 663 664 /* Unmap and put previous page of userspace buffer */ 665 static void fuse_copy_finish(struct fuse_copy_state *cs) 666 { 667 if (cs->currbuf) { 668 struct pipe_buffer *buf = cs->currbuf; 669 670 if (cs->write) 671 buf->len = PAGE_SIZE - cs->len; 672 cs->currbuf = NULL; 673 } else if (cs->pg) { 674 if (cs->write) { 675 flush_dcache_page(cs->pg); 676 set_page_dirty_lock(cs->pg); 677 } 678 put_page(cs->pg); 679 } 680 cs->pg = NULL; 681 } 682 683 /* 684 * Get another pagefull of userspace buffer, and map it to kernel 685 * address space, and lock request 686 */ 687 static int fuse_copy_fill(struct fuse_copy_state *cs) 688 { 689 struct page *page; 690 int err; 691 692 err = unlock_request(cs->req); 693 if (err) 694 return err; 695 696 fuse_copy_finish(cs); 697 if (cs->pipebufs) { 698 struct pipe_buffer *buf = cs->pipebufs; 699 700 if (!cs->write) { 701 err = pipe_buf_confirm(cs->pipe, buf); 702 if (err) 703 return err; 704 705 BUG_ON(!cs->nr_segs); 706 cs->currbuf = buf; 707 cs->pg = buf->page; 708 cs->offset = buf->offset; 709 cs->len = buf->len; 710 cs->pipebufs++; 711 cs->nr_segs--; 712 } else { 713 if (cs->nr_segs >= cs->pipe->max_usage) 714 return -EIO; 715 716 page = alloc_page(GFP_HIGHUSER); 717 if (!page) 718 return -ENOMEM; 719 720 buf->page = page; 721 buf->offset = 0; 722 buf->len = 0; 723 724 cs->currbuf = buf; 725 cs->pg = page; 726 cs->offset = 0; 727 cs->len = PAGE_SIZE; 728 cs->pipebufs++; 729 cs->nr_segs++; 730 } 731 } else { 732 size_t off; 733 err = iov_iter_get_pages2(cs->iter, &page, PAGE_SIZE, 1, &off); 734 if (err < 0) 735 return err; 736 BUG_ON(!err); 737 cs->len = err; 738 cs->offset = off; 739 cs->pg = page; 740 } 741 742 return lock_request(cs->req); 743 } 744 745 /* Do as much copy to/from userspace buffer as we can */ 746 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size) 747 { 748 unsigned ncpy = min(*size, cs->len); 749 if (val) { 750 void *pgaddr = kmap_local_page(cs->pg); 751 void *buf = pgaddr + cs->offset; 752 753 if (cs->write) 754 memcpy(buf, *val, ncpy); 755 else 756 memcpy(*val, buf, ncpy); 757 758 kunmap_local(pgaddr); 759 *val += ncpy; 760 } 761 *size -= ncpy; 762 cs->len -= ncpy; 763 cs->offset += ncpy; 764 return ncpy; 765 } 766 767 static int fuse_check_page(struct page *page) 768 { 769 if (page_mapcount(page) || 770 page->mapping != NULL || 771 (page->flags & PAGE_FLAGS_CHECK_AT_PREP & 772 ~(1 << PG_locked | 773 1 << PG_referenced | 774 1 << PG_uptodate | 775 1 << PG_lru | 776 1 << PG_active | 777 1 << PG_workingset | 778 1 << PG_reclaim | 779 1 << PG_waiters))) { 780 dump_page(page, "fuse: trying to steal weird page"); 781 return 1; 782 } 783 return 0; 784 } 785 786 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep) 787 { 788 int err; 789 struct page *oldpage = *pagep; 790 struct page *newpage; 791 struct pipe_buffer *buf = cs->pipebufs; 792 793 get_page(oldpage); 794 err = unlock_request(cs->req); 795 if (err) 796 goto out_put_old; 797 798 fuse_copy_finish(cs); 799 800 err = pipe_buf_confirm(cs->pipe, buf); 801 if (err) 802 goto out_put_old; 803 804 BUG_ON(!cs->nr_segs); 805 cs->currbuf = buf; 806 cs->len = buf->len; 807 cs->pipebufs++; 808 cs->nr_segs--; 809 810 if (cs->len != PAGE_SIZE) 811 goto out_fallback; 812 813 if (!pipe_buf_try_steal(cs->pipe, buf)) 814 goto out_fallback; 815 816 newpage = buf->page; 817 818 if (!PageUptodate(newpage)) 819 SetPageUptodate(newpage); 820 821 ClearPageMappedToDisk(newpage); 822 823 if (fuse_check_page(newpage) != 0) 824 goto out_fallback_unlock; 825 826 /* 827 * This is a new and locked page, it shouldn't be mapped or 828 * have any special flags on it 829 */ 830 if (WARN_ON(page_mapped(oldpage))) 831 goto out_fallback_unlock; 832 if (WARN_ON(page_has_private(oldpage))) 833 goto out_fallback_unlock; 834 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage))) 835 goto out_fallback_unlock; 836 if (WARN_ON(PageMlocked(oldpage))) 837 goto out_fallback_unlock; 838 839 replace_page_cache_page(oldpage, newpage); 840 841 get_page(newpage); 842 843 if (!(buf->flags & PIPE_BUF_FLAG_LRU)) 844 lru_cache_add(newpage); 845 846 /* 847 * Release while we have extra ref on stolen page. Otherwise 848 * anon_pipe_buf_release() might think the page can be reused. 849 */ 850 pipe_buf_release(cs->pipe, buf); 851 852 err = 0; 853 spin_lock(&cs->req->waitq.lock); 854 if (test_bit(FR_ABORTED, &cs->req->flags)) 855 err = -ENOENT; 856 else 857 *pagep = newpage; 858 spin_unlock(&cs->req->waitq.lock); 859 860 if (err) { 861 unlock_page(newpage); 862 put_page(newpage); 863 goto out_put_old; 864 } 865 866 unlock_page(oldpage); 867 /* Drop ref for ap->pages[] array */ 868 put_page(oldpage); 869 cs->len = 0; 870 871 err = 0; 872 out_put_old: 873 /* Drop ref obtained in this function */ 874 put_page(oldpage); 875 return err; 876 877 out_fallback_unlock: 878 unlock_page(newpage); 879 out_fallback: 880 cs->pg = buf->page; 881 cs->offset = buf->offset; 882 883 err = lock_request(cs->req); 884 if (!err) 885 err = 1; 886 887 goto out_put_old; 888 } 889 890 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page, 891 unsigned offset, unsigned count) 892 { 893 struct pipe_buffer *buf; 894 int err; 895 896 if (cs->nr_segs >= cs->pipe->max_usage) 897 return -EIO; 898 899 get_page(page); 900 err = unlock_request(cs->req); 901 if (err) { 902 put_page(page); 903 return err; 904 } 905 906 fuse_copy_finish(cs); 907 908 buf = cs->pipebufs; 909 buf->page = page; 910 buf->offset = offset; 911 buf->len = count; 912 913 cs->pipebufs++; 914 cs->nr_segs++; 915 cs->len = 0; 916 917 return 0; 918 } 919 920 /* 921 * Copy a page in the request to/from the userspace buffer. Must be 922 * done atomically 923 */ 924 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep, 925 unsigned offset, unsigned count, int zeroing) 926 { 927 int err; 928 struct page *page = *pagep; 929 930 if (page && zeroing && count < PAGE_SIZE) 931 clear_highpage(page); 932 933 while (count) { 934 if (cs->write && cs->pipebufs && page) { 935 /* 936 * Can't control lifetime of pipe buffers, so always 937 * copy user pages. 938 */ 939 if (cs->req->args->user_pages) { 940 err = fuse_copy_fill(cs); 941 if (err) 942 return err; 943 } else { 944 return fuse_ref_page(cs, page, offset, count); 945 } 946 } else if (!cs->len) { 947 if (cs->move_pages && page && 948 offset == 0 && count == PAGE_SIZE) { 949 err = fuse_try_move_page(cs, pagep); 950 if (err <= 0) 951 return err; 952 } else { 953 err = fuse_copy_fill(cs); 954 if (err) 955 return err; 956 } 957 } 958 if (page) { 959 void *mapaddr = kmap_local_page(page); 960 void *buf = mapaddr + offset; 961 offset += fuse_copy_do(cs, &buf, &count); 962 kunmap_local(mapaddr); 963 } else 964 offset += fuse_copy_do(cs, NULL, &count); 965 } 966 if (page && !cs->write) 967 flush_dcache_page(page); 968 return 0; 969 } 970 971 /* Copy pages in the request to/from userspace buffer */ 972 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, 973 int zeroing) 974 { 975 unsigned i; 976 struct fuse_req *req = cs->req; 977 struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args); 978 979 980 for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) { 981 int err; 982 unsigned int offset = ap->descs[i].offset; 983 unsigned int count = min(nbytes, ap->descs[i].length); 984 985 err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing); 986 if (err) 987 return err; 988 989 nbytes -= count; 990 } 991 return 0; 992 } 993 994 /* Copy a single argument in the request to/from userspace buffer */ 995 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) 996 { 997 while (size) { 998 if (!cs->len) { 999 int err = fuse_copy_fill(cs); 1000 if (err) 1001 return err; 1002 } 1003 fuse_copy_do(cs, &val, &size); 1004 } 1005 return 0; 1006 } 1007 1008 /* Copy request arguments to/from userspace buffer */ 1009 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, 1010 unsigned argpages, struct fuse_arg *args, 1011 int zeroing) 1012 { 1013 int err = 0; 1014 unsigned i; 1015 1016 for (i = 0; !err && i < numargs; i++) { 1017 struct fuse_arg *arg = &args[i]; 1018 if (i == numargs - 1 && argpages) 1019 err = fuse_copy_pages(cs, arg->size, zeroing); 1020 else 1021 err = fuse_copy_one(cs, arg->value, arg->size); 1022 } 1023 return err; 1024 } 1025 1026 static int forget_pending(struct fuse_iqueue *fiq) 1027 { 1028 return fiq->forget_list_head.next != NULL; 1029 } 1030 1031 static int request_pending(struct fuse_iqueue *fiq) 1032 { 1033 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) || 1034 forget_pending(fiq); 1035 } 1036 1037 /* 1038 * Transfer an interrupt request to userspace 1039 * 1040 * Unlike other requests this is assembled on demand, without a need 1041 * to allocate a separate fuse_req structure. 1042 * 1043 * Called with fiq->lock held, releases it 1044 */ 1045 static int fuse_read_interrupt(struct fuse_iqueue *fiq, 1046 struct fuse_copy_state *cs, 1047 size_t nbytes, struct fuse_req *req) 1048 __releases(fiq->lock) 1049 { 1050 struct fuse_in_header ih; 1051 struct fuse_interrupt_in arg; 1052 unsigned reqsize = sizeof(ih) + sizeof(arg); 1053 int err; 1054 1055 list_del_init(&req->intr_entry); 1056 memset(&ih, 0, sizeof(ih)); 1057 memset(&arg, 0, sizeof(arg)); 1058 ih.len = reqsize; 1059 ih.opcode = FUSE_INTERRUPT; 1060 ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT); 1061 arg.unique = req->in.h.unique; 1062 1063 spin_unlock(&fiq->lock); 1064 if (nbytes < reqsize) 1065 return -EINVAL; 1066 1067 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1068 if (!err) 1069 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1070 fuse_copy_finish(cs); 1071 1072 return err ? err : reqsize; 1073 } 1074 1075 struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq, 1076 unsigned int max, 1077 unsigned int *countp) 1078 { 1079 struct fuse_forget_link *head = fiq->forget_list_head.next; 1080 struct fuse_forget_link **newhead = &head; 1081 unsigned count; 1082 1083 for (count = 0; *newhead != NULL && count < max; count++) 1084 newhead = &(*newhead)->next; 1085 1086 fiq->forget_list_head.next = *newhead; 1087 *newhead = NULL; 1088 if (fiq->forget_list_head.next == NULL) 1089 fiq->forget_list_tail = &fiq->forget_list_head; 1090 1091 if (countp != NULL) 1092 *countp = count; 1093 1094 return head; 1095 } 1096 EXPORT_SYMBOL(fuse_dequeue_forget); 1097 1098 static int fuse_read_single_forget(struct fuse_iqueue *fiq, 1099 struct fuse_copy_state *cs, 1100 size_t nbytes) 1101 __releases(fiq->lock) 1102 { 1103 int err; 1104 struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL); 1105 struct fuse_forget_in arg = { 1106 .nlookup = forget->forget_one.nlookup, 1107 }; 1108 struct fuse_in_header ih = { 1109 .opcode = FUSE_FORGET, 1110 .nodeid = forget->forget_one.nodeid, 1111 .unique = fuse_get_unique(fiq), 1112 .len = sizeof(ih) + sizeof(arg), 1113 }; 1114 1115 spin_unlock(&fiq->lock); 1116 kfree(forget); 1117 if (nbytes < ih.len) 1118 return -EINVAL; 1119 1120 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1121 if (!err) 1122 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1123 fuse_copy_finish(cs); 1124 1125 if (err) 1126 return err; 1127 1128 return ih.len; 1129 } 1130 1131 static int fuse_read_batch_forget(struct fuse_iqueue *fiq, 1132 struct fuse_copy_state *cs, size_t nbytes) 1133 __releases(fiq->lock) 1134 { 1135 int err; 1136 unsigned max_forgets; 1137 unsigned count; 1138 struct fuse_forget_link *head; 1139 struct fuse_batch_forget_in arg = { .count = 0 }; 1140 struct fuse_in_header ih = { 1141 .opcode = FUSE_BATCH_FORGET, 1142 .unique = fuse_get_unique(fiq), 1143 .len = sizeof(ih) + sizeof(arg), 1144 }; 1145 1146 if (nbytes < ih.len) { 1147 spin_unlock(&fiq->lock); 1148 return -EINVAL; 1149 } 1150 1151 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one); 1152 head = fuse_dequeue_forget(fiq, max_forgets, &count); 1153 spin_unlock(&fiq->lock); 1154 1155 arg.count = count; 1156 ih.len += count * sizeof(struct fuse_forget_one); 1157 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1158 if (!err) 1159 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1160 1161 while (head) { 1162 struct fuse_forget_link *forget = head; 1163 1164 if (!err) { 1165 err = fuse_copy_one(cs, &forget->forget_one, 1166 sizeof(forget->forget_one)); 1167 } 1168 head = forget->next; 1169 kfree(forget); 1170 } 1171 1172 fuse_copy_finish(cs); 1173 1174 if (err) 1175 return err; 1176 1177 return ih.len; 1178 } 1179 1180 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq, 1181 struct fuse_copy_state *cs, 1182 size_t nbytes) 1183 __releases(fiq->lock) 1184 { 1185 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL) 1186 return fuse_read_single_forget(fiq, cs, nbytes); 1187 else 1188 return fuse_read_batch_forget(fiq, cs, nbytes); 1189 } 1190 1191 /* 1192 * Read a single request into the userspace filesystem's buffer. This 1193 * function waits until a request is available, then removes it from 1194 * the pending list and copies request data to userspace buffer. If 1195 * no reply is needed (FORGET) or request has been aborted or there 1196 * was an error during the copying then it's finished by calling 1197 * fuse_request_end(). Otherwise add it to the processing list, and set 1198 * the 'sent' flag. 1199 */ 1200 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, 1201 struct fuse_copy_state *cs, size_t nbytes) 1202 { 1203 ssize_t err; 1204 struct fuse_conn *fc = fud->fc; 1205 struct fuse_iqueue *fiq = &fc->iq; 1206 struct fuse_pqueue *fpq = &fud->pq; 1207 struct fuse_req *req; 1208 struct fuse_args *args; 1209 unsigned reqsize; 1210 unsigned int hash; 1211 1212 /* 1213 * Require sane minimum read buffer - that has capacity for fixed part 1214 * of any request header + negotiated max_write room for data. 1215 * 1216 * Historically libfuse reserves 4K for fixed header room, but e.g. 1217 * GlusterFS reserves only 80 bytes 1218 * 1219 * = `sizeof(fuse_in_header) + sizeof(fuse_write_in)` 1220 * 1221 * which is the absolute minimum any sane filesystem should be using 1222 * for header room. 1223 */ 1224 if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER, 1225 sizeof(struct fuse_in_header) + 1226 sizeof(struct fuse_write_in) + 1227 fc->max_write)) 1228 return -EINVAL; 1229 1230 restart: 1231 for (;;) { 1232 spin_lock(&fiq->lock); 1233 if (!fiq->connected || request_pending(fiq)) 1234 break; 1235 spin_unlock(&fiq->lock); 1236 1237 if (file->f_flags & O_NONBLOCK) 1238 return -EAGAIN; 1239 err = wait_event_interruptible_exclusive(fiq->waitq, 1240 !fiq->connected || request_pending(fiq)); 1241 if (err) 1242 return err; 1243 } 1244 1245 if (!fiq->connected) { 1246 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1247 goto err_unlock; 1248 } 1249 1250 if (!list_empty(&fiq->interrupts)) { 1251 req = list_entry(fiq->interrupts.next, struct fuse_req, 1252 intr_entry); 1253 return fuse_read_interrupt(fiq, cs, nbytes, req); 1254 } 1255 1256 if (forget_pending(fiq)) { 1257 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0) 1258 return fuse_read_forget(fc, fiq, cs, nbytes); 1259 1260 if (fiq->forget_batch <= -8) 1261 fiq->forget_batch = 16; 1262 } 1263 1264 req = list_entry(fiq->pending.next, struct fuse_req, list); 1265 clear_bit(FR_PENDING, &req->flags); 1266 list_del_init(&req->list); 1267 spin_unlock(&fiq->lock); 1268 1269 args = req->args; 1270 reqsize = req->in.h.len; 1271 1272 /* If request is too large, reply with an error and restart the read */ 1273 if (nbytes < reqsize) { 1274 req->out.h.error = -EIO; 1275 /* SETXATTR is special, since it may contain too large data */ 1276 if (args->opcode == FUSE_SETXATTR) 1277 req->out.h.error = -E2BIG; 1278 fuse_request_end(req); 1279 goto restart; 1280 } 1281 spin_lock(&fpq->lock); 1282 /* 1283 * Must not put request on fpq->io queue after having been shut down by 1284 * fuse_abort_conn() 1285 */ 1286 if (!fpq->connected) { 1287 req->out.h.error = err = -ECONNABORTED; 1288 goto out_end; 1289 1290 } 1291 list_add(&req->list, &fpq->io); 1292 spin_unlock(&fpq->lock); 1293 cs->req = req; 1294 err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h)); 1295 if (!err) 1296 err = fuse_copy_args(cs, args->in_numargs, args->in_pages, 1297 (struct fuse_arg *) args->in_args, 0); 1298 fuse_copy_finish(cs); 1299 spin_lock(&fpq->lock); 1300 clear_bit(FR_LOCKED, &req->flags); 1301 if (!fpq->connected) { 1302 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1303 goto out_end; 1304 } 1305 if (err) { 1306 req->out.h.error = -EIO; 1307 goto out_end; 1308 } 1309 if (!test_bit(FR_ISREPLY, &req->flags)) { 1310 err = reqsize; 1311 goto out_end; 1312 } 1313 hash = fuse_req_hash(req->in.h.unique); 1314 list_move_tail(&req->list, &fpq->processing[hash]); 1315 __fuse_get_request(req); 1316 set_bit(FR_SENT, &req->flags); 1317 spin_unlock(&fpq->lock); 1318 /* matches barrier in request_wait_answer() */ 1319 smp_mb__after_atomic(); 1320 if (test_bit(FR_INTERRUPTED, &req->flags)) 1321 queue_interrupt(req); 1322 fuse_put_request(req); 1323 1324 return reqsize; 1325 1326 out_end: 1327 if (!test_bit(FR_PRIVATE, &req->flags)) 1328 list_del_init(&req->list); 1329 spin_unlock(&fpq->lock); 1330 fuse_request_end(req); 1331 return err; 1332 1333 err_unlock: 1334 spin_unlock(&fiq->lock); 1335 return err; 1336 } 1337 1338 static int fuse_dev_open(struct inode *inode, struct file *file) 1339 { 1340 /* 1341 * The fuse device's file's private_data is used to hold 1342 * the fuse_conn(ection) when it is mounted, and is used to 1343 * keep track of whether the file has been mounted already. 1344 */ 1345 file->private_data = NULL; 1346 return 0; 1347 } 1348 1349 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to) 1350 { 1351 struct fuse_copy_state cs; 1352 struct file *file = iocb->ki_filp; 1353 struct fuse_dev *fud = fuse_get_dev(file); 1354 1355 if (!fud) 1356 return -EPERM; 1357 1358 if (!user_backed_iter(to)) 1359 return -EINVAL; 1360 1361 fuse_copy_init(&cs, 1, to); 1362 1363 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to)); 1364 } 1365 1366 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, 1367 struct pipe_inode_info *pipe, 1368 size_t len, unsigned int flags) 1369 { 1370 int total, ret; 1371 int page_nr = 0; 1372 struct pipe_buffer *bufs; 1373 struct fuse_copy_state cs; 1374 struct fuse_dev *fud = fuse_get_dev(in); 1375 1376 if (!fud) 1377 return -EPERM; 1378 1379 bufs = kvmalloc_array(pipe->max_usage, sizeof(struct pipe_buffer), 1380 GFP_KERNEL); 1381 if (!bufs) 1382 return -ENOMEM; 1383 1384 fuse_copy_init(&cs, 1, NULL); 1385 cs.pipebufs = bufs; 1386 cs.pipe = pipe; 1387 ret = fuse_dev_do_read(fud, in, &cs, len); 1388 if (ret < 0) 1389 goto out; 1390 1391 if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) { 1392 ret = -EIO; 1393 goto out; 1394 } 1395 1396 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) { 1397 /* 1398 * Need to be careful about this. Having buf->ops in module 1399 * code can Oops if the buffer persists after module unload. 1400 */ 1401 bufs[page_nr].ops = &nosteal_pipe_buf_ops; 1402 bufs[page_nr].flags = 0; 1403 ret = add_to_pipe(pipe, &bufs[page_nr++]); 1404 if (unlikely(ret < 0)) 1405 break; 1406 } 1407 if (total) 1408 ret = total; 1409 out: 1410 for (; page_nr < cs.nr_segs; page_nr++) 1411 put_page(bufs[page_nr].page); 1412 1413 kvfree(bufs); 1414 return ret; 1415 } 1416 1417 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, 1418 struct fuse_copy_state *cs) 1419 { 1420 struct fuse_notify_poll_wakeup_out outarg; 1421 int err = -EINVAL; 1422 1423 if (size != sizeof(outarg)) 1424 goto err; 1425 1426 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1427 if (err) 1428 goto err; 1429 1430 fuse_copy_finish(cs); 1431 return fuse_notify_poll_wakeup(fc, &outarg); 1432 1433 err: 1434 fuse_copy_finish(cs); 1435 return err; 1436 } 1437 1438 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, 1439 struct fuse_copy_state *cs) 1440 { 1441 struct fuse_notify_inval_inode_out outarg; 1442 int err = -EINVAL; 1443 1444 if (size != sizeof(outarg)) 1445 goto err; 1446 1447 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1448 if (err) 1449 goto err; 1450 fuse_copy_finish(cs); 1451 1452 down_read(&fc->killsb); 1453 err = fuse_reverse_inval_inode(fc, outarg.ino, 1454 outarg.off, outarg.len); 1455 up_read(&fc->killsb); 1456 return err; 1457 1458 err: 1459 fuse_copy_finish(cs); 1460 return err; 1461 } 1462 1463 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, 1464 struct fuse_copy_state *cs) 1465 { 1466 struct fuse_notify_inval_entry_out outarg; 1467 int err = -ENOMEM; 1468 char *buf; 1469 struct qstr name; 1470 1471 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1472 if (!buf) 1473 goto err; 1474 1475 err = -EINVAL; 1476 if (size < sizeof(outarg)) 1477 goto err; 1478 1479 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1480 if (err) 1481 goto err; 1482 1483 err = -ENAMETOOLONG; 1484 if (outarg.namelen > FUSE_NAME_MAX) 1485 goto err; 1486 1487 err = -EINVAL; 1488 if (size != sizeof(outarg) + outarg.namelen + 1) 1489 goto err; 1490 1491 name.name = buf; 1492 name.len = outarg.namelen; 1493 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1494 if (err) 1495 goto err; 1496 fuse_copy_finish(cs); 1497 buf[outarg.namelen] = 0; 1498 1499 down_read(&fc->killsb); 1500 err = fuse_reverse_inval_entry(fc, outarg.parent, 0, &name); 1501 up_read(&fc->killsb); 1502 kfree(buf); 1503 return err; 1504 1505 err: 1506 kfree(buf); 1507 fuse_copy_finish(cs); 1508 return err; 1509 } 1510 1511 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size, 1512 struct fuse_copy_state *cs) 1513 { 1514 struct fuse_notify_delete_out outarg; 1515 int err = -ENOMEM; 1516 char *buf; 1517 struct qstr name; 1518 1519 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1520 if (!buf) 1521 goto err; 1522 1523 err = -EINVAL; 1524 if (size < sizeof(outarg)) 1525 goto err; 1526 1527 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1528 if (err) 1529 goto err; 1530 1531 err = -ENAMETOOLONG; 1532 if (outarg.namelen > FUSE_NAME_MAX) 1533 goto err; 1534 1535 err = -EINVAL; 1536 if (size != sizeof(outarg) + outarg.namelen + 1) 1537 goto err; 1538 1539 name.name = buf; 1540 name.len = outarg.namelen; 1541 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1542 if (err) 1543 goto err; 1544 fuse_copy_finish(cs); 1545 buf[outarg.namelen] = 0; 1546 1547 down_read(&fc->killsb); 1548 err = fuse_reverse_inval_entry(fc, outarg.parent, outarg.child, &name); 1549 up_read(&fc->killsb); 1550 kfree(buf); 1551 return err; 1552 1553 err: 1554 kfree(buf); 1555 fuse_copy_finish(cs); 1556 return err; 1557 } 1558 1559 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, 1560 struct fuse_copy_state *cs) 1561 { 1562 struct fuse_notify_store_out outarg; 1563 struct inode *inode; 1564 struct address_space *mapping; 1565 u64 nodeid; 1566 int err; 1567 pgoff_t index; 1568 unsigned int offset; 1569 unsigned int num; 1570 loff_t file_size; 1571 loff_t end; 1572 1573 err = -EINVAL; 1574 if (size < sizeof(outarg)) 1575 goto out_finish; 1576 1577 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1578 if (err) 1579 goto out_finish; 1580 1581 err = -EINVAL; 1582 if (size - sizeof(outarg) != outarg.size) 1583 goto out_finish; 1584 1585 nodeid = outarg.nodeid; 1586 1587 down_read(&fc->killsb); 1588 1589 err = -ENOENT; 1590 inode = fuse_ilookup(fc, nodeid, NULL); 1591 if (!inode) 1592 goto out_up_killsb; 1593 1594 mapping = inode->i_mapping; 1595 index = outarg.offset >> PAGE_SHIFT; 1596 offset = outarg.offset & ~PAGE_MASK; 1597 file_size = i_size_read(inode); 1598 end = outarg.offset + outarg.size; 1599 if (end > file_size) { 1600 file_size = end; 1601 fuse_write_update_attr(inode, file_size, outarg.size); 1602 } 1603 1604 num = outarg.size; 1605 while (num) { 1606 struct page *page; 1607 unsigned int this_num; 1608 1609 err = -ENOMEM; 1610 page = find_or_create_page(mapping, index, 1611 mapping_gfp_mask(mapping)); 1612 if (!page) 1613 goto out_iput; 1614 1615 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1616 err = fuse_copy_page(cs, &page, offset, this_num, 0); 1617 if (!err && offset == 0 && 1618 (this_num == PAGE_SIZE || file_size == end)) 1619 SetPageUptodate(page); 1620 unlock_page(page); 1621 put_page(page); 1622 1623 if (err) 1624 goto out_iput; 1625 1626 num -= this_num; 1627 offset = 0; 1628 index++; 1629 } 1630 1631 err = 0; 1632 1633 out_iput: 1634 iput(inode); 1635 out_up_killsb: 1636 up_read(&fc->killsb); 1637 out_finish: 1638 fuse_copy_finish(cs); 1639 return err; 1640 } 1641 1642 struct fuse_retrieve_args { 1643 struct fuse_args_pages ap; 1644 struct fuse_notify_retrieve_in inarg; 1645 }; 1646 1647 static void fuse_retrieve_end(struct fuse_mount *fm, struct fuse_args *args, 1648 int error) 1649 { 1650 struct fuse_retrieve_args *ra = 1651 container_of(args, typeof(*ra), ap.args); 1652 1653 release_pages(ra->ap.pages, ra->ap.num_pages); 1654 kfree(ra); 1655 } 1656 1657 static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode, 1658 struct fuse_notify_retrieve_out *outarg) 1659 { 1660 int err; 1661 struct address_space *mapping = inode->i_mapping; 1662 pgoff_t index; 1663 loff_t file_size; 1664 unsigned int num; 1665 unsigned int offset; 1666 size_t total_len = 0; 1667 unsigned int num_pages; 1668 struct fuse_conn *fc = fm->fc; 1669 struct fuse_retrieve_args *ra; 1670 size_t args_size = sizeof(*ra); 1671 struct fuse_args_pages *ap; 1672 struct fuse_args *args; 1673 1674 offset = outarg->offset & ~PAGE_MASK; 1675 file_size = i_size_read(inode); 1676 1677 num = min(outarg->size, fc->max_write); 1678 if (outarg->offset > file_size) 1679 num = 0; 1680 else if (outarg->offset + num > file_size) 1681 num = file_size - outarg->offset; 1682 1683 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; 1684 num_pages = min(num_pages, fc->max_pages); 1685 1686 args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0])); 1687 1688 ra = kzalloc(args_size, GFP_KERNEL); 1689 if (!ra) 1690 return -ENOMEM; 1691 1692 ap = &ra->ap; 1693 ap->pages = (void *) (ra + 1); 1694 ap->descs = (void *) (ap->pages + num_pages); 1695 1696 args = &ap->args; 1697 args->nodeid = outarg->nodeid; 1698 args->opcode = FUSE_NOTIFY_REPLY; 1699 args->in_numargs = 2; 1700 args->in_pages = true; 1701 args->end = fuse_retrieve_end; 1702 1703 index = outarg->offset >> PAGE_SHIFT; 1704 1705 while (num && ap->num_pages < num_pages) { 1706 struct page *page; 1707 unsigned int this_num; 1708 1709 page = find_get_page(mapping, index); 1710 if (!page) 1711 break; 1712 1713 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1714 ap->pages[ap->num_pages] = page; 1715 ap->descs[ap->num_pages].offset = offset; 1716 ap->descs[ap->num_pages].length = this_num; 1717 ap->num_pages++; 1718 1719 offset = 0; 1720 num -= this_num; 1721 total_len += this_num; 1722 index++; 1723 } 1724 ra->inarg.offset = outarg->offset; 1725 ra->inarg.size = total_len; 1726 args->in_args[0].size = sizeof(ra->inarg); 1727 args->in_args[0].value = &ra->inarg; 1728 args->in_args[1].size = total_len; 1729 1730 err = fuse_simple_notify_reply(fm, args, outarg->notify_unique); 1731 if (err) 1732 fuse_retrieve_end(fm, args, err); 1733 1734 return err; 1735 } 1736 1737 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size, 1738 struct fuse_copy_state *cs) 1739 { 1740 struct fuse_notify_retrieve_out outarg; 1741 struct fuse_mount *fm; 1742 struct inode *inode; 1743 u64 nodeid; 1744 int err; 1745 1746 err = -EINVAL; 1747 if (size != sizeof(outarg)) 1748 goto copy_finish; 1749 1750 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1751 if (err) 1752 goto copy_finish; 1753 1754 fuse_copy_finish(cs); 1755 1756 down_read(&fc->killsb); 1757 err = -ENOENT; 1758 nodeid = outarg.nodeid; 1759 1760 inode = fuse_ilookup(fc, nodeid, &fm); 1761 if (inode) { 1762 err = fuse_retrieve(fm, inode, &outarg); 1763 iput(inode); 1764 } 1765 up_read(&fc->killsb); 1766 1767 return err; 1768 1769 copy_finish: 1770 fuse_copy_finish(cs); 1771 return err; 1772 } 1773 1774 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, 1775 unsigned int size, struct fuse_copy_state *cs) 1776 { 1777 /* Don't try to move pages (yet) */ 1778 cs->move_pages = 0; 1779 1780 switch (code) { 1781 case FUSE_NOTIFY_POLL: 1782 return fuse_notify_poll(fc, size, cs); 1783 1784 case FUSE_NOTIFY_INVAL_INODE: 1785 return fuse_notify_inval_inode(fc, size, cs); 1786 1787 case FUSE_NOTIFY_INVAL_ENTRY: 1788 return fuse_notify_inval_entry(fc, size, cs); 1789 1790 case FUSE_NOTIFY_STORE: 1791 return fuse_notify_store(fc, size, cs); 1792 1793 case FUSE_NOTIFY_RETRIEVE: 1794 return fuse_notify_retrieve(fc, size, cs); 1795 1796 case FUSE_NOTIFY_DELETE: 1797 return fuse_notify_delete(fc, size, cs); 1798 1799 default: 1800 fuse_copy_finish(cs); 1801 return -EINVAL; 1802 } 1803 } 1804 1805 /* Look up request on processing list by unique ID */ 1806 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique) 1807 { 1808 unsigned int hash = fuse_req_hash(unique); 1809 struct fuse_req *req; 1810 1811 list_for_each_entry(req, &fpq->processing[hash], list) { 1812 if (req->in.h.unique == unique) 1813 return req; 1814 } 1815 return NULL; 1816 } 1817 1818 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args, 1819 unsigned nbytes) 1820 { 1821 unsigned reqsize = sizeof(struct fuse_out_header); 1822 1823 reqsize += fuse_len_args(args->out_numargs, args->out_args); 1824 1825 if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar)) 1826 return -EINVAL; 1827 else if (reqsize > nbytes) { 1828 struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1]; 1829 unsigned diffsize = reqsize - nbytes; 1830 1831 if (diffsize > lastarg->size) 1832 return -EINVAL; 1833 lastarg->size -= diffsize; 1834 } 1835 return fuse_copy_args(cs, args->out_numargs, args->out_pages, 1836 args->out_args, args->page_zeroing); 1837 } 1838 1839 /* 1840 * Write a single reply to a request. First the header is copied from 1841 * the write buffer. The request is then searched on the processing 1842 * list by the unique ID found in the header. If found, then remove 1843 * it from the list and copy the rest of the buffer to the request. 1844 * The request is finished by calling fuse_request_end(). 1845 */ 1846 static ssize_t fuse_dev_do_write(struct fuse_dev *fud, 1847 struct fuse_copy_state *cs, size_t nbytes) 1848 { 1849 int err; 1850 struct fuse_conn *fc = fud->fc; 1851 struct fuse_pqueue *fpq = &fud->pq; 1852 struct fuse_req *req; 1853 struct fuse_out_header oh; 1854 1855 err = -EINVAL; 1856 if (nbytes < sizeof(struct fuse_out_header)) 1857 goto out; 1858 1859 err = fuse_copy_one(cs, &oh, sizeof(oh)); 1860 if (err) 1861 goto copy_finish; 1862 1863 err = -EINVAL; 1864 if (oh.len != nbytes) 1865 goto copy_finish; 1866 1867 /* 1868 * Zero oh.unique indicates unsolicited notification message 1869 * and error contains notification code. 1870 */ 1871 if (!oh.unique) { 1872 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs); 1873 goto out; 1874 } 1875 1876 err = -EINVAL; 1877 if (oh.error <= -512 || oh.error > 0) 1878 goto copy_finish; 1879 1880 spin_lock(&fpq->lock); 1881 req = NULL; 1882 if (fpq->connected) 1883 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT); 1884 1885 err = -ENOENT; 1886 if (!req) { 1887 spin_unlock(&fpq->lock); 1888 goto copy_finish; 1889 } 1890 1891 /* Is it an interrupt reply ID? */ 1892 if (oh.unique & FUSE_INT_REQ_BIT) { 1893 __fuse_get_request(req); 1894 spin_unlock(&fpq->lock); 1895 1896 err = 0; 1897 if (nbytes != sizeof(struct fuse_out_header)) 1898 err = -EINVAL; 1899 else if (oh.error == -ENOSYS) 1900 fc->no_interrupt = 1; 1901 else if (oh.error == -EAGAIN) 1902 err = queue_interrupt(req); 1903 1904 fuse_put_request(req); 1905 1906 goto copy_finish; 1907 } 1908 1909 clear_bit(FR_SENT, &req->flags); 1910 list_move(&req->list, &fpq->io); 1911 req->out.h = oh; 1912 set_bit(FR_LOCKED, &req->flags); 1913 spin_unlock(&fpq->lock); 1914 cs->req = req; 1915 if (!req->args->page_replace) 1916 cs->move_pages = 0; 1917 1918 if (oh.error) 1919 err = nbytes != sizeof(oh) ? -EINVAL : 0; 1920 else 1921 err = copy_out_args(cs, req->args, nbytes); 1922 fuse_copy_finish(cs); 1923 1924 spin_lock(&fpq->lock); 1925 clear_bit(FR_LOCKED, &req->flags); 1926 if (!fpq->connected) 1927 err = -ENOENT; 1928 else if (err) 1929 req->out.h.error = -EIO; 1930 if (!test_bit(FR_PRIVATE, &req->flags)) 1931 list_del_init(&req->list); 1932 spin_unlock(&fpq->lock); 1933 1934 fuse_request_end(req); 1935 out: 1936 return err ? err : nbytes; 1937 1938 copy_finish: 1939 fuse_copy_finish(cs); 1940 goto out; 1941 } 1942 1943 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from) 1944 { 1945 struct fuse_copy_state cs; 1946 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp); 1947 1948 if (!fud) 1949 return -EPERM; 1950 1951 if (!user_backed_iter(from)) 1952 return -EINVAL; 1953 1954 fuse_copy_init(&cs, 0, from); 1955 1956 return fuse_dev_do_write(fud, &cs, iov_iter_count(from)); 1957 } 1958 1959 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, 1960 struct file *out, loff_t *ppos, 1961 size_t len, unsigned int flags) 1962 { 1963 unsigned int head, tail, mask, count; 1964 unsigned nbuf; 1965 unsigned idx; 1966 struct pipe_buffer *bufs; 1967 struct fuse_copy_state cs; 1968 struct fuse_dev *fud; 1969 size_t rem; 1970 ssize_t ret; 1971 1972 fud = fuse_get_dev(out); 1973 if (!fud) 1974 return -EPERM; 1975 1976 pipe_lock(pipe); 1977 1978 head = pipe->head; 1979 tail = pipe->tail; 1980 mask = pipe->ring_size - 1; 1981 count = head - tail; 1982 1983 bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL); 1984 if (!bufs) { 1985 pipe_unlock(pipe); 1986 return -ENOMEM; 1987 } 1988 1989 nbuf = 0; 1990 rem = 0; 1991 for (idx = tail; idx != head && rem < len; idx++) 1992 rem += pipe->bufs[idx & mask].len; 1993 1994 ret = -EINVAL; 1995 if (rem < len) 1996 goto out_free; 1997 1998 rem = len; 1999 while (rem) { 2000 struct pipe_buffer *ibuf; 2001 struct pipe_buffer *obuf; 2002 2003 if (WARN_ON(nbuf >= count || tail == head)) 2004 goto out_free; 2005 2006 ibuf = &pipe->bufs[tail & mask]; 2007 obuf = &bufs[nbuf]; 2008 2009 if (rem >= ibuf->len) { 2010 *obuf = *ibuf; 2011 ibuf->ops = NULL; 2012 tail++; 2013 pipe->tail = tail; 2014 } else { 2015 if (!pipe_buf_get(pipe, ibuf)) 2016 goto out_free; 2017 2018 *obuf = *ibuf; 2019 obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 2020 obuf->len = rem; 2021 ibuf->offset += obuf->len; 2022 ibuf->len -= obuf->len; 2023 } 2024 nbuf++; 2025 rem -= obuf->len; 2026 } 2027 pipe_unlock(pipe); 2028 2029 fuse_copy_init(&cs, 0, NULL); 2030 cs.pipebufs = bufs; 2031 cs.nr_segs = nbuf; 2032 cs.pipe = pipe; 2033 2034 if (flags & SPLICE_F_MOVE) 2035 cs.move_pages = 1; 2036 2037 ret = fuse_dev_do_write(fud, &cs, len); 2038 2039 pipe_lock(pipe); 2040 out_free: 2041 for (idx = 0; idx < nbuf; idx++) { 2042 struct pipe_buffer *buf = &bufs[idx]; 2043 2044 if (buf->ops) 2045 pipe_buf_release(pipe, buf); 2046 } 2047 pipe_unlock(pipe); 2048 2049 kvfree(bufs); 2050 return ret; 2051 } 2052 2053 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait) 2054 { 2055 __poll_t mask = EPOLLOUT | EPOLLWRNORM; 2056 struct fuse_iqueue *fiq; 2057 struct fuse_dev *fud = fuse_get_dev(file); 2058 2059 if (!fud) 2060 return EPOLLERR; 2061 2062 fiq = &fud->fc->iq; 2063 poll_wait(file, &fiq->waitq, wait); 2064 2065 spin_lock(&fiq->lock); 2066 if (!fiq->connected) 2067 mask = EPOLLERR; 2068 else if (request_pending(fiq)) 2069 mask |= EPOLLIN | EPOLLRDNORM; 2070 spin_unlock(&fiq->lock); 2071 2072 return mask; 2073 } 2074 2075 /* Abort all requests on the given list (pending or processing) */ 2076 static void end_requests(struct list_head *head) 2077 { 2078 while (!list_empty(head)) { 2079 struct fuse_req *req; 2080 req = list_entry(head->next, struct fuse_req, list); 2081 req->out.h.error = -ECONNABORTED; 2082 clear_bit(FR_SENT, &req->flags); 2083 list_del_init(&req->list); 2084 fuse_request_end(req); 2085 } 2086 } 2087 2088 static void end_polls(struct fuse_conn *fc) 2089 { 2090 struct rb_node *p; 2091 2092 p = rb_first(&fc->polled_files); 2093 2094 while (p) { 2095 struct fuse_file *ff; 2096 ff = rb_entry(p, struct fuse_file, polled_node); 2097 wake_up_interruptible_all(&ff->poll_wait); 2098 2099 p = rb_next(p); 2100 } 2101 } 2102 2103 /* 2104 * Abort all requests. 2105 * 2106 * Emergency exit in case of a malicious or accidental deadlock, or just a hung 2107 * filesystem. 2108 * 2109 * The same effect is usually achievable through killing the filesystem daemon 2110 * and all users of the filesystem. The exception is the combination of an 2111 * asynchronous request and the tricky deadlock (see 2112 * Documentation/filesystems/fuse.rst). 2113 * 2114 * Aborting requests under I/O goes as follows: 1: Separate out unlocked 2115 * requests, they should be finished off immediately. Locked requests will be 2116 * finished after unlock; see unlock_request(). 2: Finish off the unlocked 2117 * requests. It is possible that some request will finish before we can. This 2118 * is OK, the request will in that case be removed from the list before we touch 2119 * it. 2120 */ 2121 void fuse_abort_conn(struct fuse_conn *fc) 2122 { 2123 struct fuse_iqueue *fiq = &fc->iq; 2124 2125 spin_lock(&fc->lock); 2126 if (fc->connected) { 2127 struct fuse_dev *fud; 2128 struct fuse_req *req, *next; 2129 LIST_HEAD(to_end); 2130 unsigned int i; 2131 2132 /* Background queuing checks fc->connected under bg_lock */ 2133 spin_lock(&fc->bg_lock); 2134 fc->connected = 0; 2135 spin_unlock(&fc->bg_lock); 2136 2137 fuse_set_initialized(fc); 2138 list_for_each_entry(fud, &fc->devices, entry) { 2139 struct fuse_pqueue *fpq = &fud->pq; 2140 2141 spin_lock(&fpq->lock); 2142 fpq->connected = 0; 2143 list_for_each_entry_safe(req, next, &fpq->io, list) { 2144 req->out.h.error = -ECONNABORTED; 2145 spin_lock(&req->waitq.lock); 2146 set_bit(FR_ABORTED, &req->flags); 2147 if (!test_bit(FR_LOCKED, &req->flags)) { 2148 set_bit(FR_PRIVATE, &req->flags); 2149 __fuse_get_request(req); 2150 list_move(&req->list, &to_end); 2151 } 2152 spin_unlock(&req->waitq.lock); 2153 } 2154 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2155 list_splice_tail_init(&fpq->processing[i], 2156 &to_end); 2157 spin_unlock(&fpq->lock); 2158 } 2159 spin_lock(&fc->bg_lock); 2160 fc->blocked = 0; 2161 fc->max_background = UINT_MAX; 2162 flush_bg_queue(fc); 2163 spin_unlock(&fc->bg_lock); 2164 2165 spin_lock(&fiq->lock); 2166 fiq->connected = 0; 2167 list_for_each_entry(req, &fiq->pending, list) 2168 clear_bit(FR_PENDING, &req->flags); 2169 list_splice_tail_init(&fiq->pending, &to_end); 2170 while (forget_pending(fiq)) 2171 kfree(fuse_dequeue_forget(fiq, 1, NULL)); 2172 wake_up_all(&fiq->waitq); 2173 spin_unlock(&fiq->lock); 2174 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 2175 end_polls(fc); 2176 wake_up_all(&fc->blocked_waitq); 2177 spin_unlock(&fc->lock); 2178 2179 end_requests(&to_end); 2180 } else { 2181 spin_unlock(&fc->lock); 2182 } 2183 } 2184 EXPORT_SYMBOL_GPL(fuse_abort_conn); 2185 2186 void fuse_wait_aborted(struct fuse_conn *fc) 2187 { 2188 /* matches implicit memory barrier in fuse_drop_waiting() */ 2189 smp_mb(); 2190 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0); 2191 } 2192 2193 int fuse_dev_release(struct inode *inode, struct file *file) 2194 { 2195 struct fuse_dev *fud = fuse_get_dev(file); 2196 2197 if (fud) { 2198 struct fuse_conn *fc = fud->fc; 2199 struct fuse_pqueue *fpq = &fud->pq; 2200 LIST_HEAD(to_end); 2201 unsigned int i; 2202 2203 spin_lock(&fpq->lock); 2204 WARN_ON(!list_empty(&fpq->io)); 2205 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2206 list_splice_init(&fpq->processing[i], &to_end); 2207 spin_unlock(&fpq->lock); 2208 2209 end_requests(&to_end); 2210 2211 /* Are we the last open device? */ 2212 if (atomic_dec_and_test(&fc->dev_count)) { 2213 WARN_ON(fc->iq.fasync != NULL); 2214 fuse_abort_conn(fc); 2215 } 2216 fuse_dev_free(fud); 2217 } 2218 return 0; 2219 } 2220 EXPORT_SYMBOL_GPL(fuse_dev_release); 2221 2222 static int fuse_dev_fasync(int fd, struct file *file, int on) 2223 { 2224 struct fuse_dev *fud = fuse_get_dev(file); 2225 2226 if (!fud) 2227 return -EPERM; 2228 2229 /* No locking - fasync_helper does its own locking */ 2230 return fasync_helper(fd, file, on, &fud->fc->iq.fasync); 2231 } 2232 2233 static int fuse_device_clone(struct fuse_conn *fc, struct file *new) 2234 { 2235 struct fuse_dev *fud; 2236 2237 if (new->private_data) 2238 return -EINVAL; 2239 2240 fud = fuse_dev_alloc_install(fc); 2241 if (!fud) 2242 return -ENOMEM; 2243 2244 new->private_data = fud; 2245 atomic_inc(&fc->dev_count); 2246 2247 return 0; 2248 } 2249 2250 static long fuse_dev_ioctl(struct file *file, unsigned int cmd, 2251 unsigned long arg) 2252 { 2253 int res; 2254 int oldfd; 2255 struct fuse_dev *fud = NULL; 2256 2257 switch (cmd) { 2258 case FUSE_DEV_IOC_CLONE: 2259 res = -EFAULT; 2260 if (!get_user(oldfd, (__u32 __user *)arg)) { 2261 struct file *old = fget(oldfd); 2262 2263 res = -EINVAL; 2264 if (old) { 2265 /* 2266 * Check against file->f_op because CUSE 2267 * uses the same ioctl handler. 2268 */ 2269 if (old->f_op == file->f_op && 2270 old->f_cred->user_ns == file->f_cred->user_ns) 2271 fud = fuse_get_dev(old); 2272 2273 if (fud) { 2274 mutex_lock(&fuse_mutex); 2275 res = fuse_device_clone(fud->fc, file); 2276 mutex_unlock(&fuse_mutex); 2277 } 2278 fput(old); 2279 } 2280 } 2281 break; 2282 default: 2283 res = -ENOTTY; 2284 break; 2285 } 2286 return res; 2287 } 2288 2289 const struct file_operations fuse_dev_operations = { 2290 .owner = THIS_MODULE, 2291 .open = fuse_dev_open, 2292 .llseek = no_llseek, 2293 .read_iter = fuse_dev_read, 2294 .splice_read = fuse_dev_splice_read, 2295 .write_iter = fuse_dev_write, 2296 .splice_write = fuse_dev_splice_write, 2297 .poll = fuse_dev_poll, 2298 .release = fuse_dev_release, 2299 .fasync = fuse_dev_fasync, 2300 .unlocked_ioctl = fuse_dev_ioctl, 2301 .compat_ioctl = compat_ptr_ioctl, 2302 }; 2303 EXPORT_SYMBOL_GPL(fuse_dev_operations); 2304 2305 static struct miscdevice fuse_miscdevice = { 2306 .minor = FUSE_MINOR, 2307 .name = "fuse", 2308 .fops = &fuse_dev_operations, 2309 }; 2310 2311 int __init fuse_dev_init(void) 2312 { 2313 int err = -ENOMEM; 2314 fuse_req_cachep = kmem_cache_create("fuse_request", 2315 sizeof(struct fuse_req), 2316 0, 0, NULL); 2317 if (!fuse_req_cachep) 2318 goto out; 2319 2320 err = misc_register(&fuse_miscdevice); 2321 if (err) 2322 goto out_cache_clean; 2323 2324 return 0; 2325 2326 out_cache_clean: 2327 kmem_cache_destroy(fuse_req_cachep); 2328 out: 2329 return err; 2330 } 2331 2332 void fuse_dev_cleanup(void) 2333 { 2334 misc_deregister(&fuse_miscdevice); 2335 kmem_cache_destroy(fuse_req_cachep); 2336 } 2337